Underreamer



E. A. BUCHANAN UNDERREAMER Dec. 10, 1929.

Filed Sept. 24, 1925' 2 Sheets-Sheet gva/vento@ 2 Sheets-Sheet 2 Dec l0, 1929. E. A. BUCHANAN UNDERREAMER Filed sept. 24. 1925 Patented Dec. l0, 1929 PATENT OFFICE UNDERREAMEB i .application mea september 24, 1925. seran No. 58,457.

This invention is a reamer for oil and gas wells and has for its object the provision of means whereby the surface of the oil or gas bearing sand may be cleaned and the well enlarged to provide free flow of the oil or gas. Secondary objects of the invention are to provide means whereby the'cuttings may be driven from the well without requiring a rem'oval of the reamer; to providea structure 'whereby the pressure iiuid employed for removing the-cuttings may 'be supplied through the reamer; to provide means whereby the reamer may be held in a relatively fixed position when the cuttings are being blown from the well, and to provide means whereby the choking of the reamerwill be prevented. Other objects of the invention will appear incidentally in the course of the following description and the invention resides in certain novel features which will be particularly pointed out in the appended claims.

In the accompanying drawings which illustrate one embodiment of the invention,

Figure 1 is a sectional elevation showing the reamer in position in a well;

Fig. 2 is an enlarged longitudinal section of the reamer;

Fig. 3 is a side elevationl of the head by 3o which the reamer is connected with the tublng i Fig. 4 is a bottom plan View of the head shown in Fig. 3, and

Fig. 5 is an enlarged perspective view of a portionof a cutter.

Referring more particularly to Fig; 1, the well casing is indicated at 1 and the tubing which carries the pump for extracting the oil or gas is indicated at 2. Ordinarily, the

4o lower end of the well is of cylindrical formation having' a diameter approximately the same as the inner diameter of the casing 1 and a pump head is attached to the lower end of the tubing 2, and the tubing-serves as a means for actuating the pump under power from a source upon the surface of the ground. The surface of the Well in time becomes clogged or coated with paraiin, tar or other impurities contained in the oil or to -gas so that the seepage is` reduced and requently entirely stopped. Under these coni creased capacity. Itis now the general practice to remove the tubing, detach the pump therefrom and substitute for the pump a reamer which is then lowered in the well with the tubing and rotated so as to clean the surface of the sand and enlarge the well chamber. The tubing is then removed and the reamer detached, after which the tubing is again inserted and utilized as a conduit to direct compressed air or other Huid under pressure into the well chamber so that the cuttings will be blown out through the casing-around the tubing. My invention provides means whereby the removal of the reamer is unnecessary and the compressed air or other pressure iiuid may be introduced while the reamer is still attached to the tubmg.

In carrying out my invention, I provide a head 3, the upper end of which is reduced in diameter relative to its lower end and is externally threaded, as shown at 4, whereby 1t may be easily secured in the lower end of a collar connectino' it with the tubing, as shown in Fig. 2. The lower end ofthe head 3 1s notched or slotted, as shown at 5, and extending outwardly from the walls of the slot are radial openings 6 which are adapted to receive pivots carrying the reamer 7. The interior of the head 3 is enlarged at its lower end to provide a chamber 8 in which the spherical head 9 at the upper end of the reamer is received so that, while the reamer will be securely carried by the head, the reamer may swing laterally when in use so as to `extend through the slots or notches 5 and assume an angular relation to the tubing and the head. The head 9 of the reamer is rovided at diametrically op osite points with ivots 10 inserted throng the openings 6 o the head 3, as will be understood u on reference to Fig'- ure 2. At the lower en of the threaded portion 4 of the coupling head 3 are radial vents 11 and the bore of the head in its upper portion is enlarged, as shown at 12, to house a coiled spring 13 which bears at one end against the annular shoulder presented by the said en` larged` bore and at its opposite end against the under side of an annular flange 14 at the upper end of a locking sleeve or thimble 15 which lits within the bore of the head snugly but slidably. In the upper extremity of the head is secured a stop collar or ring 16 whereby the upward movement of the locking sleeve is limited and it is retained within the head at all times. It will beY noted that the bore of the sleeve is of less diameter than the locking ring so that the upper end of the sleeve is exposed to the'pressure of the fluid iowing through the tubing 2 into the reamer and will, by reason of such pressure, be forced 'downwardly against the tension of the spring 13. The lower end of the locking sleeve is beveled, as shown at 17, and in the upper extremity of the reamer is a beveled seat 18 which is adapted to be engaged by the said beveled surface 17. When the pressure fluid is admitted to the casing 2 andxiows through the same, it will at first act upon the upper end of the locking sleeve and will thereby drive the sleeve downward so that its beveled end 17 will engage the seat 18 and thereby lock the. reamer against pivotal movement. The vents 11 will accommodate any seepage or leakage of the pressure fluid around the'ends of the locking sleeve so that pressure cannot-be built up in the chamber 12 to prematurely unseat the sleeve.

As clearly shown in Fig. 2, the reamer is hollow or of tubular form -and it is provided near its upper end with an annular external rib 19, the purpose of which will presently appear. Fitted upon the body of the reamer below the said rib 19 are cutters each consisting of a sleeve or cylindrical body 20 of such diameter that it will fit closely about the reamer, and teeth or cutting points 21 formed upon or secured to the outer surface of the sleeve. These teeth or cutting points are ot' such form that they present a triangular face 22 in the direction of rotation of the reamer and taper from said triangular face, as shown at 23 in Fig. 5. The lower end of each tube or cutter sleeve 20 is countersunk, as shown at 24, and the upper extremity of each tube'is beveled, as indicated at 25, while the lowermost teeth of each tube are extended' below the lower end thereof, as show-n at 26. The beveled surfaces 25 permit the sleeves to it closely to the under beveled surface of the rib 19 and to the under surface ofthe lower teeth 26 respectively, while the countersunk portions 24 accommodate a spring 27. In the drawings, I have .shown'thespring 27 as housed within' the vcountersink of the lowermost cutter member only, but it will be understood, of course, that if 'so desired a spring mayl be inserted in the countersunk lower end of each cutter section. The spring has its ends bearing against the shoulder presented by the'countersink' and the annular liange on the cutter retainer, respectively, so that the cutter will be held tothe reamer to rotate therewithbut may yield to a limited extent so that breakage of the cutter 'upon encountering a hard substance, such as gravel, will be avoided. A cutter retainer 28 is provided at the lower end of the reamer body to support the spring 27 and also engage the lower end of the lowest cutter section, thereby retaining the cutters. positively upon the reamer. In the present instance, this retainer is shown as an annular flange at the lower end of a valve cage 29 which is threaded into the lower end of the reamer and carries a valve 30which normally closes the end of the reamer. The particular form of valve may be varied to suit the preferences of any particular operator, and 1n the present case is illustratedY as a disk having a stem 31 rising through a guide 32 carried by the valve cage, the valve being held normally seated by a spring 33 'coiled around the upper end of the stem and bearingupon the guide and an abutment 34 at the end of the stem. It will be noted that the lower teeth 26 of the lowest cutter section project below the plane of the valve so that in use they will make a cavity or cut at such apoint as to provide clearance for the surface of the valve. The valve is normally seated and will remain seated as long as no pressure iuid is admitted to the reamer and, consequently, the entrance of cuttings into the reamer is prevented and choking ofthe reamer is thereby avoided.

When the reaming of the well becomes necessary, the tubing 2 is withdrawn and the pump head is removed therefrom. The coupling head 3 carrying the reamer 7 is then secured in the lower end of the tubing and the tubing with the attached reamer again loweredinto the well. The tubin is then rotated and, of course, the head 3 an the reamer will rotate therewith but, under centrifugal action, the reamer will swing about the pivots 10 through the slots or notches 5 from the perpendicular position shown in full lines in Fig. 1 to the position shown in dotted lines in said figure so that as the rotation of the tubing continues the reamer will cut against the surface of the sand and will enlarge the well chamber which eventually will assume the' substantially triangular or hemispherical form illustrated in Fic. 1, the cuttings accumulating in the bottom, of the enlarged chamber, as indicated at 35. 'When the chamber has been sufi'ciently enlarged, rotation of the tubing 2 is discontinued and the reamer will then resume the perpendicular position shown in full lines in Fig. 1. The reamer may be of any length, according to the diameter desired for the reamed portion of the well and its lower end may be originally accommodated in a sump, indicated at 36. The

ing sand and if it should be lowered so as to rest heavily on the cuttings so that the valve cannot open, it may be lifted slightly to give the valve clearance. After' the cuttings are in motion, the reamer may belowered, if necessary, to thoroughly clean the weil. ,The rotation of the tubing having stopped, as stated, compressed air or other pressure fluid is admitted to the tubing and will, of course, flow downwardly through the same driving the locking sleeve into engagement with the upper end of the reamer'so that it willthen be held against lateral swinging movement. The force ofthe fluid will obviously open the valve and the luid will then escape through the lower end of the reamer and be admitted into the body of cuttings. The fluid, of course, seeks an escape and this escape is provided through the casing 1 around the tubing 2 so that the cuttings will be blown upwardly through the casing with the escaping pressure fluid. When all the cuttings have been blown out,the flow of pressure fluid is arrested` the tubing with the reamer withdrawn and the pump head then substituted for the reamer, after which the normal operation ofthe well is, resumed. It will be readily seen from the foregoing description, taken in connection with the accompanying drawings., that I have provided an exceedingly` simple mechanism whereby the work of rcaming an oil or gas well will be very materially expedited and the cost of the operation reduced.

' The cutters which are fitted upon the reamer are interchangeable so that they may be shifted relative to each other uponthe reamer to compensate for unequal wear upon the points and also provide for the use of as many or as few cutters as may be advantageous under any given conditions. Ther cutter points are each in the form of a tetrahedron so that they will work readily through the sand and the accumulated matter coating the same while they also provide a substantial cutting edge or edges and the resistance to their progress through the sand or other body will be minimized. The access of material into the reamer during the cutting operation is effectually prevented while during the blowing operation the pivotal movement of the reamer is positively prevented and, therefore, the pressure fluid in escaping from the lower end of the reamer will act inall directions upon the body'of cuttings.

Having thus described the invention, I

` claim 1. Means for reaming an oil or gas well comprising in combination with a rotatable tubing` a tubular reamer having its upper end pivoted -directly to the lower end of the tubing at a relatively fixed center of pivotal movement and forming a closed joint withI the tubing, the entire reamer below the tubing being unrestrained whereby it may re- Aspond to centrifugal action and having its borecommunicating directly with the bore of the tubing at all times.

2. Means for the purpose set forth comprising a tubular reamer, means for connecting the reamer to the lower end of a tubing to rotate therewith and have pivotal movement relative thereto, yieldable means for normally closing the lower end of the reamer, and means for locking the reamer against pivotal movement.

3. A reamer for wells comprising a tubular body, means for pivotally connecting the upper end of said body with the lower end of the well tubinfr whereby said' body will rotate with the tu ing and may swing laterally relative thereto, the bore ofthe tubular body being in direct communication with the bore of the well tubing, and cutter members frictio'nally mounted upon the circumference ot Y the reamer body to rotate therewith.

4. A reamer for wells comprising a tubular reamer body, means for connecting said body with the lower end of well tubing, a retaining rib on the said body, a retainer at the lower end of the body, aplurality of cutter sections comprising tubular bodies litting closely around the reamer body and having countersank lower ends and cutting points projecting from the outer surface of each of said cutter bodies,v and a spring housed within the countersunk end of one of4 the cutter sections whereby the ends of the several cutter sections will be held in contact and against the retainers on the reamer body.

5. A reamer for Wells comprising a tubular body, means for connecting the upper end of said body with Well tubing, a valve mounted at and normally closing the lower end ot said reamer body, and cutters carried eX- ternally by and encircling said reamer body with the lowermost cutters projecting below the valve.

6. A reamer for wells comprising a tubular body` cutters carried externally of said body` a valve closing the lower end of the said body, a coupling head fitting' over the upper end of the reamer body and having pivotal connection therewith, the up er end of said coupling head being adapte to be secured in the lower end of well tubing, and a locking sleeve mounted in the upper end of said head and adapted to engage the upper end of the reamer body whereby to lock the said body against pivotal movement. v

7. A reamer for wells comprising a tubular reamer body, cutters carried externally by said body, a valve normally closing the lower end of the body, a coupling head fitting over the upper end of the reamer body and pivotally connected therewith, the upper extremity of said head being adapted to be sccured in the lower end of Well tubing, a locking sleeve slidably motmted in the upper end of the head and having its lower crd constructed to engage the upper end of the reamer body and lock said body against pivotal movement, theupper endV of the sleeve extending into the path of pressure Huid adi mitted through the well tubing to the head .ot'al connection therewith, the bore o said head being enlarged its upper portion and th head being provided with lateral vents -`near the lower end of said enlarged bore,

, means for connectingsaid head to well tubing, a locking sleeve slidably fitted in the bore of the head and adapted to engage the upper end of the reamer body to lock the same against pivotal movement, said locking sleeve being provided with a lateral shoulder at its upper end, an expansion spring inthe enlarged bore ot the gcoupling head bearing against the lower end of said bore and the underside of said shoulder, and a stop ring fitted in the upper end of the head above the locking sleeve, the inner diameterY of said stop ring being greater-than the inner diameter of thelocking sleeve.

9. Means for the purpose set forth -comprising a tubular reamer body,means-t'or pivotally connecting said body to well tubing with its 'bore in communication with the bore of the well tubing, means for locking the reamer body against pivotal movement, and means in the lower end of the reamer body to prevent How into the same but permit outflow of pressure fiuid.y

' 10. Means for 'the purpose set `forth comprising a tubular reamer body, means for pivotally connecting said body to Well tubing with its bore in communication with the bore of the well tubing, means for locking the reamer body against pivotal movement, and a valve mounted in the lower end of the re'amer body to close the same against inflow from the well but arranged to open to permit outflow-of pressure fluid from the well tubing.

1L A reamer for wells comprising a tubular reamer body, cutters encirclingand carried by said body, a coupling head fitting over theupper end of the reamer body and. having pivotal vconnection therewith, the bore of said head being enlarged in its upper portion and the head being provided with lateral vents near the lower end of fsaid enlarged bore, means for connecting said head to well tubing, a locking sleeve slidably fitted in the enlarged bore of the head .and adapted to engage the upper end of the reamer body to lock the same against .pivotal movement, yieldable means for holding the locking sleeve out of engagement with the reamer body, and means to limit the movement of the locking sleeve under the induence of said yieldable means.

In testimony whereof I aiix my signature.

EMMOR A. BUCHANAN. [1.. s.] 

